Method of manufacturing optical interference color display

ABSTRACT

The method of manufacturing an optical interference color display is described. A first electrode structure is formed over a substrate first. At least one first area, second area and third area are defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure of the first area, the second area and the third area. Moreover, a second sacrificial layer is formed over the first sacrificial layer inside the second area and the third area. In addition, a third sacrificial layer is formed over the second sacrificial layer inside the third area. The etching rates of all sacrificial layers are different. Then, a patterned support layer is formed over the first electrode structure. Next, a second electrode layer is formed and the sacrificial layers are removed to form air gaps. Therefore, the air gaps are effectively controlled by using the material having different etching rates.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser. No. 11/133,641, filed on May 20, 2005, which claims the priority benefit of Taiwan application serial no. 94103551, filed on Feb. 4, 2005. The disclosures of both applications are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of fabricating an optical interference color display, and more particularly to a method of fabricating an optical interference color display capable of controlling air gaps formed in the optical interference color display precisely.

2. Description of the Related Art

Panel displays, such as liquid crystal (LCD) displays, organic electro-luminescence (OEL) displays, or plasma display panels (PDPs), which are light and slim, have been widely used in our daily life. Wherein, LCD displays have gradually dominated the market. However, LCD displays still have some disadvantages. For example, the angles are not wide enough, the response time is not fast, and requirement of using polarizer results in poor utilization of light source.

An optical interference color display has been developed to date. FIG. 1 is a schematic drawing showing a conventional optical interference color display. The conventional optical interference color display 100 comprises a transparent substrate 110, a first electrode structure 120, a patterned support layer 130 and a second electrode layer 140. The first electrode structure 120 comprises a plurality of first electrodes 122, an absorption layer 124 and an optical layer 126, from bottom to top. Note that a plurality of air gaps G1-G3 is formed (defined) between the first electrode structure 120 and the optical layer 126.

After propagating into the first electrode structure 120 through the transparent substrate 110, light propagates to the first electrode structure 120 through the air gaps G1-G3. Then, the light is reflected by the second electrode layer 140 and propagates through the first electrode structure 120. Due to different light interferences in the different air gaps G1-G3, different color lights, such as red, green and blue lights, are generated for displaying. The forming of the air gaps G1-G3, however, is determined by the thicknesses of the sacrificial layers. Detailed description will be mentioned later. In other words, the quality of the sacrificial layers will affect the optical performance of the optical interference color display 100.

FIGS. 2A-2D are cross sectional views showing progress of a method of forming sacrificial layers. Referring to FIG. 2A, a transparent substrate 110 is provided. A first electrode structure 120 is then formed over the transparent substrate 110. The first electrode structure 120 comprises a plurality of first electrodes 122, an absorption layer 124 and an optical layer 126, from bottom to top. In addition, a first area 10, a second area 20 and a third area 30 are defined on the first electrode structure 120.

Referring to FIG. 2B, a first sacrificial layer 132, e.g., amorphous silicon, is entirely deposited. A photolithographic process and an etch process are performed to remove the first sacrificial layer 132 outside the first area 10, the second area 20 and the third area 30 to form a first sacrificial layer 132 with designated patterning.

Referring to FIG. 2C, a second sacrificial layer 134 is entirely deposited. The second sacrificial layer 134 and the first sacrificial layer 132 are the same material. A photolithographic process and an etch process are performed to remove the second sacrificial layer 134 outside the second area 20 and the third area 30 to form a second sacrificial layer 134 with designated patterning. Note that while removing the second sacrificial layer 134 of the first area 10 by the etch process, the first sacrificial layer 132 and the second sacrificial layer 134 are the same material, i.e., the same etching rate. Accordingly, the first sacrificial layer 132 is easily damaged by the etchant used in the etch process such that the original thickness of the sacrificial layer 132 is changed. That causes impact to the subsequent processes.

Referring to FIG. 2D, a third sacrificial layer 136 is entirely deposited. The third sacrificial layer 136, the second sacrificial layer 134 and the first sacrificial layer 132 are the same material. A photolithographic process and an etch process are performed to remove the third sacrificial layer 136 outside the third area 30 to form a third sacrificial layer 136 with designated patterning. The process of forming the sacrificial layers is thus complete. Note that the third sacrificial layer 136 is on the first sacrificial layer 132 while the third sacrificial layer 136 of the first area 10 is removed by the etch process, thus the first sacrificial layer 132 is damaged easily. Similarly, while removing the third sacrificial layer 136 of the second area 20, the third sacrificial layer 136 is on the first sacrificial layer 132, and the first sacrificial layer 132 and the third sacrificial layer 136 have the same etching rate. Accordingly, while the third sacrificial layer 136 is removed, the second sacrificial layer 134 is also damaged easily.

Finally, a photoresist layer is entirely coated. The photoresist layer is then patterned to form a patterned support layer 130. Then, a second electrode layer 140 is formed over the sacrificial layers with different thicknesses of the first area 10, the second area 20 and the third area 30, and a portion of the patterned support layer 130. Thereafter, etchant, such as XeF₆, is then used to remove all sacrificial layers 132, 134 and 136 to form different air gaps G1-G3 as shown in FIG. 1.

In other words, the thicknesses of the deposited sacrificial layers determine the formation of the air gaps G1-G3. If the desired thicknesses of the sacrificial layers are changed due to the damaged sacrificial layers, the dimensions of the air gaps G1-G3 cannot be precisely controlled. The optical performance of the optical interference color display 100 is seriously affected. Under the described unstable manufacturing processes, yields are declined and manufacturing costs are also increased.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method of fabricating an optical interference color display. In this method, the thicknesses of the sacrificial layers can be precisely controlled so that better air gaps can be obtained.

The present invention is also directed to a method of fabricating an optical interference color display. In this method, better air gaps can be formed, and the optical performance of the optical interference color display can be enhanced.

As embodied and broadly described herein, a method of fabricating an optical interference color display is provided. In this method, a substrate is first provided. A first electrode structure is formed over the substrate. A first area, a second area and a third area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area, the second area and the third area. A second sacrificial layer is then formed over the first sacrificial layer inside the second area and the third area. A third sacrificial layer is formed over the second sacrificial layer inside the third area. The first sacrificial layer, the second sacrificial layer and the third sacrificial have different etching rates. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area, and a portion of the patterned support layer. Finally, the first sacrificial layer, the second sacrificial layer and the third sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the substrate comprises, for example, a glass substrate or a plastic substrate.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the method of forming the first electrode structure comprises the following steps. A plurality of first electrodes is formed over the substrate. An absorption layer is then formed over the first electrodes. Finally, an optical layer is formed over the absorption layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the first electrodes are, for example, transparent electrodes, and the material of the first electrodes comprises, for example, indium tin oxide (ITO).

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the absorption layer comprises, for example, Chromium (Cr) or Molybdenum chromium (MoCr).

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the optical layer comprises, for example, silicon nitride or silicon oxide.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the patterned support layer comprises, for example, a photoresist layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the etching rate of the second sacrificial layer is more than 1.5 times of the etching rate of the first sacrificial layer, and the etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the second electrode layer is a metal electrode. The material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof, for example.

As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is provided first. A first electrode structure is formed over the substrate. A first area, a second area, and a third area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area. A second sacrificial layer is formed over the first electrode structure inside the second area. A third sacrificial layer is formed over the first electrode structure inside the third area. The first sacrificial layer, the second sacrificial layer and the third sacrificial have different etching rates and thicknesses. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area, and a portion of the patterned support layer. Finally, the first sacrificial layer, the second sacrificial layer and the third sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the substrate comprises, for example, a glass substrate or a plastic substrate.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the method of forming the first electrode structure comprises the following steps. A plurality of first electrodes is formed over the substrate. An absorption layer is then formed over the first electrodes. Finally, an optical layer is formed over the absorption layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the first electrodes are, for example, transparent electrodes, and the material of the first electrodes comprises, for example, indium tin oxide (ITO).

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the absorption layer comprises, for example, Chromium (Cr) or Molybdenum chromium (MoCr).

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the optical layer comprises, for example, silicon nitride or silicon oxide.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the patterned support layer comprises, for example, a photoresist layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the etching rate of the second sacrificial layer is more than 1.5 times of the etching rate of the first sacrificial layer, and the etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example.

According to the method of fabricating the optical interference color display in accordance with an embodiment of the present invention, the second electrode layer is a metal electrode. The material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof, for example.

As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is first provided. A first electrode structure is formed over the substrate. A first area and a second area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area and the second area. A second sacrificial layer is then formed over the first sacrificial layer inside the second area. The first sacrificial layer and the second sacrificial layer have different etching rates. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, and a portion of the patterned support layer. Finally, the first sacrificial layer and the second sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.

As embodied and broadly described herein, the present invention provides a method of fabricating an optical interference color display. In this method, a substrate is provided first. A first electrode structure is formed over the substrate. A first area and a second area are then defined on the first electrode structure. A first sacrificial layer is formed over the first electrode structure inside the first area. A second sacrificial layer is formed over the first electrode structure inside the second area. The first sacrificial layer and the second sacrificial layer have different etching rates and thicknesses. A patterned support layer is then formed over the first electrode structure. A second electrode layer is formed over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, and a portion of the patterned support layer. Finally, the first sacrificial layer and the second sacrificial layer are removed to form a plurality of air gaps between the first electrode structure and the second electrode layer.

In the method of fabricating the optical interference color display, materials with different etching rates are used to form sacrificial layers. As a result, the sacrificial layers have different etching rates. While being etched, damage to the sacrificial layers can be prevented, and the better air gaps can be obtained. Accordingly, the optical performance of the optical interference color display can be improved.

The above and other features of the present invention will be better understood from the following detailed description of the preferred embodiments of the invention that is provided in communication with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing showing a conventional optical interference color display.

FIGS. 2A-2D are cross sectional views showing progress of a method of forming sacrificial layers.

FIGS. 3A-3F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the first embodiment of the present invention.

FIGS. 4A-4F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT First Embodiment

FIGS. 3A-3F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the first embodiment of the present invention. Referring to FIG. 3A, a transparent substrate 210 is provided. Its material can be, for example, glass or plastic. A first electrode structure 220 is then formed over the transparent substrate 210.

The method of forming the first electrode structure 220 can be, for example, a physical vapor deposition (PVD) process or other suitable processes, to deposit indium tin oxide (ITO) over the transparent substrate 210. The ITO layer is then patterned by a photolithographic process and an etching process to form a plurality of first transparent electrodes 222. An absorption layer 224 is then deposited over the first electrodes 222 and partial area of the substrate 210 where no first electrodes 222 are formed. In one embodiment of the present invention, the material of the absorption layer 224 can be, for example, Chromium (Cr) or Molybdenum chromium (MoCr).

Finally, an optical layer 226 is deposited over the absorption layer 224. Wherein, the material of the optical layer 226 can be, for example, silicon nitride or silicon oxide. Of course, the optical layer 226 is not limited to a single layer. It may comprise a plurality of dielectric layers with high refractive index and a plurality of dielectric layers with high refractive index stacked alternately. The steps described above form the first electrode structure 220. The first electrode structure 220 comprises the first electrodes 222, the absorption layer 224 and the optical layer 226. In addition, the first area 10, the second area 20 and the third area 30 are defined on the first electrode structure 220.

Referring to FIG. 3B, a first sacrificial layer 232 is entirely deposited. Its material can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. Then, a photolithographic process and an etching process are performed to remove the first sacrificial layer 232 outside the first area 10, the second area 20 and the third area 30 to form the first sacrificial layer 232 with designated patterning.

Referring to FIG. 3C, a second sacrificial layer 234 is entirely deposited. The second sacrificial layer 234 has an etching rate at least more than 1.5 times of that of the first sacrificial layer 232. The material of the second sacrificial layer 234 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. In some embodiments, as long as the etching rate of the second sacrificial layer 234 is higher than that of the first sacrificial layer 232, the material with etching rate higher than the etching rate of the first sacrificial layer 232 mentioned above can be used as the second sacrificial layer 234. For example, the first and the second sacrificial layers may be formed of the same material, such as amorphous silicon. They are then processed under different temperatures so that the first sacrificial layer 232 and the second sacrificial layer 234 have different etching rates. Nevertheless, as long as the materials have different etching rates to the same or different etchants, the materials can be used.

A photolithographic process and an etching process are then performed to remove the second sacrificial layer 234 outside the second area 20 and the third area 30 to form the patterned sacrificial layer 234 with designated patterning. Note that the second sacrificial layer 234 is over the first sacrificial layer 232 while the second sacrificial layer 234 inside the first area 10 is removed. The etch process can be, for example, a wet etch process or other suitable processes to remove the second sacrificial layer 234. Since the second sacrificial layer 234 has a higher etching rate, damage to the first sacrificial layer 232 can be reduced while the etch process is removing the second sacrificial layer 234. Accordingly, the thickness of the first sacrificial layer 232 can be maintained.

Referring to FIG. 3D, a third sacrificial layer 236 is then entirely deposited. A photolithographic process and an etch process are performed to remove the third sacrificial layer 236 outside the third area 30 to form the third sacrificial layer 236 with designated patterning. The fabrication of the sacrificial layers inside the first area 10, the second area 20 and the third area 30 are thus accomplished.

Note that in order to pattern the third sacrificial layer 236, a wet etch process or other suitable process is used to remove the third sacrificial layer 236 inside the first area 10 and the third sacrificial layer 236 inside the second area 20. The etching rate of the third sacrificial layer 236 of the first area 10 is higher than that of the first sacrificial layer 232. Though the first sacrificial layer 232 is under the second sacrificial layer 234, the first sacrificial layer 232 will not be damaged while the third sacrificial layer 236 is removed.

Similarly, the etching rate of the third sacrificial layer 236 of the second area 20 is more than 1.5 times of that of the second sacrificial layer 234, for example. Though the second sacrificial layer 234 is under the third sacrificial layer 236, damage to the second sacrificial layer 234 can be reduced due to their different etching rates. In addition, the thicknesses of the sacrificial layers 232, 234, 236 can be well controlled. It should be noted that the removing process of the sacrificial layers 232, 234, 236 is so call releasing process.

Referring to FIG. 3E, a photoresist layer is entirely coated. The photoresist layer is then patterned to form the patterned support layer 230. Then, a second electrode layer 240 is entirely deposited. The material of the second electrode layer 240 can be a light-reflective metal, such as Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, or a combination thereof. A photolithographic process and an etch process are then performed to form the patterned second electrode layer 240. The second electrode layer 240 is formed over the first sacrificial layer 232 inside the first area 10, the second sacrificial layer 234 inside the second area 20, the third sacrificial layer 236 inside the third area 30 and a portion of the patterned support layer 230.

Referring to FIG. 3F, all of these sacrificial layers are removed by using suitable etchant, e.g. XeF₆ to form different air gaps C1, C2 and C3. In detail, after forming the second electrode layer 240 over the sacrificial layers with different thicknesses and performing releasing process, different air gaps C1, C2 and C3 can be formed simultaneously. In addition, the air gaps C1, C2 and C3 generally are smaller than, or equal to 1 μm. In this embodiment, the sacrificial layers have different etching rates. By depositing the sacrificial layer with a smaller etching rate first, damage to the earlier-deposited sacrificial layer can be reduced.

Compared with the prior art technology, the present invention can well control the thicknesses of the sacrificial layers and improve the quality of the air gaps C1, C2, C3 and the manufacturing yields. The optical performance of the optical interference color display 200 can also be enhanced.

Second Embodiment

FIGS. 4A-4F are cross sectional views showing progress of a method of fabricating an optical interference color display according to the second embodiment of the present invention. Referring to FIG. 4A, the steps are similar to those shown in FIG. 3A. A first electrode structure 220 is formed and the first area 10, the second area 20 and the third area 30 are defined.

Referring to FIG. 4B, a first sacrificial layer 332 is entirely deposited. The material of the first sacrificial layer 332 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. Then, a photolithographic process and an etching process are performed to remove the first sacrificial layer 332 outside the first area 10 to form the first sacrificial layer 332 with designate patterning.

Referring to FIG. 4C, a second sacrificial layer 334 is entirely deposited. The material of the second sacrificial layer 334 has an etching rate at least more than 1.5 times of that of the first sacrificial layer 332, for example. The material of the second sacrificial layer 334 can be selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon, for example. In some embodiments, as long as the etching rate of the second sacrificial layer 334 is higher than that of the first sacrificial layer 332, the material of the second sacrificial layer 334 can be used. For example, the first and the second sacrificial layers may be formed of the same material, such as amorphous silicon. They are then processed under different temperatures so that the first sacrificial layer 332 and the second sacrificial layer 334 have different etching rates. Nevertheless, whether the etchants are the same or different, as long as the sacrificial layers have different etching rates, the materials can be used.

A photolithographic process and an etching process are then performed to the second sacrificial layer 334 to remove the second sacrificial layer 334 outside the second area 20 to form the second sacrificial layer 334 with designate patterning. Note that the second sacrificial layer 334 is on top of the first sacrificial layer 332 while the second sacrificial layer 334 of the first area 10 is removed. The etch process can be, for example, a wet etch process or other suitable processes to remove the second sacrificial layer 334. Since the second sacrificial layer 334 has a higher etching rate, damage to the first sacrificial layer 332 can be reduced while the second sacrificial layer 334 is removed by the etch process. Accordingly, the thickness of the first sacrificial layer 332 can be maintained.

Referring to FIG. 4D, a third sacrificial layer 336 is then entirely deposited. A photolithographic process and an etch process are performed to remove the third sacrificial layer 336 outside the third area 30 to form the third sacrificial layer 336 with designate patterning. The sacrificial layers inside the first area 10, the second area 20 and the third area 30 are thus accomplished.

Note that in order to pattern the third sacrificial layer 336, a wet etch process or other suitable process is used to remove the third sacrificial layer 336 inside the first area 10 and the third sacrificial layer 336 inside the second area 20. The etching rate of the third sacrificial layer 336 inside the first area 10 is higher than that of the first sacrificial layer 332. Though below the first sacrificial layer 332 is underneath, the first sacrificial layer 332 will not be damaged while the third sacrificial layer 336 is removed.

Similarly, the etching rate of the third sacrificial layer 336 inside the second area 20 is more than 1.5 times of that of the second sacrificial layer 334, for example. Though the second sacrificial layer 334 is below the third sacrificial layer 336, damage to the second sacrificial layer 334 can be reduced due to their different etching rates. In addition, the thicknesses of the sacrificial layers can be well controlled.

Referring to FIG. 4E, a photoresist layer is entirely coated. The photoresist layer is then patterned to form the patterned support layer 330. Then, a second electrode layer 340 is entirely deposited. The material of the second electrode layer 340 can be a light-reflective metal, such as Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, or a combination thereof. A photolithographic process and an etch process are then performed to form the second electrode layer 340 with designate patterning. The second electrode layer 340 is formed over the first sacrificial layer 332 inside the first area 10, the second sacrificial layer 334 inside the second area 20, the third sacrificial layer 336 inside the third area 30 and a portion of the patterned support layer 330.

Referring to FIG. 4F, the steps of forming different air gaps C1, C2 and C3 as shown in FIG. 3F are illustrated. In detail, after forming the second electrode layer 340 over the sacrificial layers with different thicknesses and performing releasing process, different air gaps D1, D2 and D3 can be defined. In this embodiment, by depositing the sacrificial layer with a smaller etching rate first, damage to the earlier-deposited sacrificial layer can be reduced.

Embodiments described above are methods to form the air gaps C1-C3 and D1-D3. The present invention, however, is not limited thereto. In the method of fabricating the optical interference color display of the present invention, only two different air gaps may be formed. The fabrication method is similar to that described above. What is different is that mere the first and the second sacrificial layers are formed in other embodiment In addition, in the method of fabricating the optical interference color display of the present invention, more than three different air gaps can be formed. The fabrication method is similar to that described above. What is different is that in addition to the first, the second and the third sacrificial layers, additional sacrificial layers can be formed.

Accordingly, the method of fabricating the optical interference color display comprises the following advantages:

1. In the method of fabricating the optical interference color display of the present invention, damage to the sacrificial layers can be avoided. The air gaps can be well controlled and the manufacturing yields can be improved. Accordingly, the optical performance of the optical interference color display is enhanced.

2. In the method of fabricating the optical interference color display of the present invention, materials with different etching rates are used to form the sacrificial layers. Damage to the sacrificial layers can be prevented and the thicknesses of the sacrificial layers can also be precisely controlled.

Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claims should be constructed broadly to include other variants and embodiments of the invention which may be made by those skilled in the field of this art without departing from the scope and range of equivalents of the invention. 

1. A method of fabricating an optical interference color display, comprising: providing a substrate, and forming a first electrode structure over the substrate; defining a first area, a second area, and a third area on the first electrode structure; forming a first sacrificial layer over the first electrode structure of the first area; forming a second sacrificial layer over the first electrode structure of the second area; forming a third sacrificial layer over the first electrode structure of the third area, wherein the first sacrificial layer, the second sacrificial layer and the third sacrificial layer having different etching rates and thicknesses; forming a patterned support layer over the first electrode structure; forming a second electrode layer over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area, the third sacrificial layer inside the third area and a portion of the patterned support layer; and removing the first sacrificial layer, the second sacrificial layer and the third sacrificial layer to form a plurality of air gaps between the first electrode structure and the second electrode layer.
 2. The method of fabricating an optical interference color display of claim 1, wherein the substrate comprises a glass substrate or a plastic substrate.
 3. The method of fabricating an optical interference color display of claim 1, wherein the steps of forming the first electrode structure comprise: forming a plurality of first electrodes over the substrate; forming an absorption layer over the first electrodes; and forming an optical layer over the absorption layer.
 4. The method of fabricating an optical interference color display of claim 3, wherein the first electrodes are transparent electrodes, and a material of the first electrodes comprises indium tin oxide (ITO).
 5. The method of fabricating an optical interference color display of claim 3, wherein a material of the absorption layer comprises Chromium (Cr) or Molybdenum chromium (MoCr).
 6. The method of fabricating an optical interference color display of claim 3, wherein a material of the optical layer comprises silicon nitride or silicon oxide.
 7. The method of fabricating an optical interference color display of claim 1, wherein a material of the patterned support layer comprises a photoresist layer.
 8. The method of fabricating an optical interference color display of claim 1, wherein an etching rate of the second sacrificial layer is more than 1.5 times of an etching rate of the first sacrificial layer, and an etching rate of the third sacrificial layer is more than 1.5 times of the etching rate of the second sacrificial layer.
 9. The method of fabricating an optical interference color display of claim 1, wherein a material of the first sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.
 10. The method of fabricating an optical interference color display of claim 1, wherein a material of the second sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.
 11. The method of fabricating an optical interference color display of claim 1, wherein a material of the third sacrificial layer is selected from a group consisting of MoCr, Cr, polysilicon, amorphous silicon and N-type amorphous silicon.
 12. The method of fabricating an optical interference color display of claim 1, wherein the second electrode layer is a metal electrode, and a material of the second electrode layer is selected from a group consisting of Mo, Mo alloy, aluminum, aluminum alloy, Cr, nickel, titanium, and a combination thereof.
 13. A method of fabricating an optical interference color display, comprising: providing a substrate, and forming a first electrode structure over the substrate; defining a first area and a second area on the first electrode structure; forming a first sacrificial layer over the first electrode structure of the first area; forming a second sacrificial layer over the first electrode structure of the second area, the first sacrificial layer and the second sacrificial layer having different etching rates and thicknesses; forming a patterned support layer over the first electrode structure; forming a second electrode layer over the first sacrificial layer inside the first area, the second sacrificial layer inside the second area and a portion of the patterned support layer; and removing the first sacrificial layer and the second sacrificial layer to form a plurality of air gaps between the first electrode structure and the second electrode layer. 